Poster headboard



FIG. 1 is a front view of a poster headboard showing our new design, it being understood that the back is plain and does not form a part of the claimed design;

FIG. 2 is a right side view thereof, it being understood that the opposite side is the mirror image of the side shown; and,

FIG. 3 is a top view thereof, it being understood that the bottom side is plain and does not form a part of the claimed design. 

The ornamental design for a poster headboard, as shown and described. 